A new version of Cryptolocker—dubbed Cryptolocker 2.0—has been discovered by ESET, although researchers believe it to be a copycat of the original Cryptolocker after noting large differences in the program’s code and operation.
Just last month, antivirus companies discovered a new ransomware known as Cryptolocker.
This ransomware is particularly nasty because infected users are in danger of losing their personal files forever.
Spread through email attachments, this ransomware has been seen targeting companies through phishing attacks.
Cryptolocker will encrypt users’ files using asymmetric encryption, which requires both a public and private key.
The public key is used to encrypt and verify data, while private key is used for decryption, each the inverse of the other.
Below is an image from Microsoft depicting the process of asymmetric encryption.
The bad news is decryption is impossible unless a user has the private key stored on the cybercriminals’ server.
Currently, infected users are instructed to pay $300 USD to receive this private key.
Infected users also have a time limit to send the payment.
If this time elapses, the private key is destroyed, and your files may be lost forever.
Files targeted are those commonly found on most PCs today; a list of file extensions for targeted files include: 3fr, accdb, ai, arw, bay, cdr, cer, cr2, crt, crw, dbf, dcr, der, dng, doc, docm, docx, dwg, dxf, dxg, eps, erf, indd, jpe, jpg, kdc, mdb, mdf, mef, mrw, nef, nrw, odb, odm, odp, ods, odt, orf, p12, p7b, p7c, pdd, pef, pem, pfx, ppt, pptm, pptx, psd, pst, ptx, r3d, raf, raw, rtf, rw2, rwl, srf, srw, wb2, wpd, wps, xlk, xls, xlsb, xlsm, xlsx
In some cases, it may be possible to recover previous versions of the encrypted files using System Restore or other recovery software used to obtain “shadow copies” of files. (Or by restoring a previous version from your backup – see Backup further down this article for more information)
Malwarebytes detects Cryptolocker infections as Trojan.Ransom, but it cannot recover your encrypted files due to the nature of asymmetric encryption, which requires a private key to decrypt files encrypted with the public key.
While Malwarebytes cannot recover your encrypted files post-infection, we do have options to prevent infections before they start.
Users of Malwarebytes Anti-Malware Pro are protected by malware execution prevention and blocking of malware sites and servers, though the free version can be run to detect and remove.
Also, the existence of malware such as Cryptolocker reinforces the need to back up your personal files.
However, a local backup may not be enough in some instances, as Cryptolocker may even go after backups located on a network drive connected to an infected PC.
Cloud-based backup solutions are advisable for business professionals and consumers alike. So long as you have multiple file versions, you can restore the file to a point before the infection, if you only have one Version of the file, the latest and only one may also have been infected. Good practice is to keep versions of the backed up files to allow restoring of a file to a specific point in time (before the corruption, infection or other disaster where the latest copy is not usable)